Secreted phospholipases A2 (sPLA2) form a family of structurally related enzymes that catalyze the hydrolysis of the sn-2 fatty acyl bond of phospholipids to release free fatty acids and lysophospholipids. By catalyzing this reaction, sPLA2 enzymes play a key role in various biological processes including homeostasis of cellular membranes, lipid digestion, host defense, signal transduction, and production of lipid mediators such as eicosanoids and lysophospholipid derivatives (Valentin et al. 2000, Bioch. Biophys. Act. 59-70; Lambeau, G., and Gelb, M. H. 2008, Annu. Rev. Biochem. 77, 495-520). This family comprises eleven members/isoforms named sPLA2-IB, sPLA2-IIA, sPLA2-IIC, sPLA2-IID, sPLA2-IIE, sPLA2-IIF, sPLA2-III, sPLA2-V, sPLA2-X, sPLA2-XIIA and sPLA2-XIIB.
Quantification of specific isoforms at the protein level has proven to be difficult because of similar enzymatic activities and the absence of isoform-specific sPLA2 antibodies.
Nevalainen et al. (Biochimica et Biophysica Acta 1733 (2005) 210-223) developed an antibody against sPLA2-IIA for use in a time-resolved fluoroimmunoassay (TR-FIA). This polyclonal antibody was obtained by immunizing rabbits with recombinant human sPLA2-IIA protein. The analytical sensitivity of the TR-FIA was described as 1 ng/ml.
Cayman chemical provides a monoclonal antibody under reference SCACC353. According to the experimental results obtained by the inventors, the SCACC353 antibody has a Kd for binding human sPLA2-IIA of about 1 nM (see Examples).
There is currently a need for antibodies against sPLA2-IIA that allow a more accurate and sensitive detection of sPLA2-IIA in biological sample such as serum sample.